The present invention provides ion beam sources which can address specific industrial needs. For the applications identified above, it is necessary to produce ion beams of many different charged species—a range and variety which commonly includes phosphorus, boron, carbon, nitrogen, oxygen, argon, silicon, germanium, and arsenic ions.
Such conventional applications require a high current, a range of energies from tens of eV up to one hundred keV, stability, precise control of the ions, and a long service life. High current for ion implantation demands many milliamperes of ions of the desired species, commonly more than 30 mA; and since the present invention is addressed to producing much larger ion beams of up to 1 A or more for reasons of productivity, the practitioner in the field becomes interested only in scalable ion source architectures which can produce current densities exceeding about 10 ma per sq. cm. at the exit aperture of the ion source, and which are preferably more than 30 mA/sq cm.
Also, singly-charged atomic ions are desirable in almost all conventional application instances, but sometimes molecular ions are usable. For more details and information, see two standard text books in particular: The Physics and Technology of Ion Sources, 2nd ed., Edited by Ian G. Brown, Wiley, 2004; and Large Ion Beams, A. Theodore Forrester, Wiley, 1988. Also, see U.S. Pat. Nos. 7,498,572; 8,723,135; 6,160,262; and 8,455,837 for a range of operational details.
 By commonly accepted definition, a ‘plasma’ is deemed to be the fourth state of existence for physical matter: if one increasingly heats any matter appearing as a gas [or a solid, or a liquid]—that substance will eventually accumulate and contain enough energy to enter into a plasma state, in which some electrons are freed from atoms, and a quasi-neutral mix of atoms, positive ions, electrons and sometimes negative ions will coexist. Plasma is the state of matter from which ions are most easily extracted in vacuum.
The temperature of plasma electrons is generally in excess of 10,000 degrees K; and is most conveniently measured in units of electron Volts (eV), where one eV corresponds to 11,627 K.
Although in a few specific use instances the whole plasma may be in thermal equilibrium at a uniform temperature—in the overwhelming majority of real-world plasmas in ion sources, the electrons establish a thermal equilibrium at one temperature (typically one or two eV). But the ions are not in equilibrium with the electrons, because their mass is many thousand times that of the electrons, and they may remain at a temperature closer to the gas from which they were formed. The fundamental laws of kinematics for such collisions reveals that many millions of collisions are required between electrons and atoms/ion before the ion energy begins to approach the mean energy of the electrons.
Thus, in its most generalized form, an ion source functions to produce a plasma of differently charged ion species from a preselected material or substance; and then extracts and accelerates these ion species to high velocities as a shaped “beam” in which the multiple′ ions are mono-energetic with velocities on the order of km/s.
 Accordingly, the typical gaseous substance ion source will present at least two operational parts: (i) A plasma generating system; and (ii) a beam extracting system. Each of these component systems employs tangible structures and entities to achieve its intended purpose and function.
• The plasma generator is the source's operative subunit which creates a plasma from the gaseous substance; and from which a sufficient quantity of the desired or appropriate ion species is subsequently extracted as a shaped beam by the source's extraction system. There are multiple ways of generating a plasma from the gaseous substance; but the focus today is on electron impact ionization—where ions are created by electron impact, and where the electron energy is as low as practicable, usually 40 to 120 V.
This manner of generating a plasma typically requires the presence of a source of electrons with much higher energy than the average plasma electron. Thus, the plasma source will typically contain the following: A neutral gas or vapor at ambient temperature (which may be a temperature of several hundred K in some instances); a source of electrons with energies of 40 to 120 eV, a voltage which is more than sufficient to ionize the gas (see FIG.-2); electrons liberated from gas atoms by electron or ion impact, which rapidly come to thermal equilibrium at a temperature of a few eV; and ions created by electron impact, and which will have initial temperatures close to ambient, but which on leaving the plasma may have a mean energy value which is a sizeable fraction of the electron temperature. It is also desirable that the density of the ions be high and that their temperature be as low as possible.
• In noted contrast then, the ion source's extraction system is the operative subunit which accelerates the ions from the plasma, and produces a flowing ion beam of the desired shape and correct divergence angle for transport to its destination. Neutral particles and electrons are respectively ignored and repelled by the extraction system. Extraction systems for high current positive beams utilize a minimum of three electrodes, as shown in Prior Art FIG. 1.
 It is therefore deemed useful here to present an accurate summary description not only of how ribbon shaped ion beams are created and what were the major advances occurring over time within the field itself; but also to identify correctly what constitutes the prevailing views and dominant vantage points of persons working today in this technical area.